18
FO 935 ETH
FAN TEST
It is possible, by programming (
HFn
), to make sure that the fans are operated for 5 minutes every
xxx
” hours, regardless of
the temperature values of the columns or the environment (e.g.: with HFn = 001 the fans are activated for 5 minutes every
hour).
This function is designed to periodically check the operation of the fans and of their control equipment.
Setting
NO
, this function is inhibited.
To enable the HFN function, read the programming section on pages 19-20.
FAIL-SAFE FUNCTION
The FO 935 control unit has the selection n.o (normally open contact) / n.c (normally closed contact) for the ALARM, TRIP
and FAULT relays, programming steps from 26 to 31 page 20.Selecting the YES/NO setting introduces the Fail Safe and
No Fail Safe functions.
ALARM AND TRIP
By setting NO (NO Fail safe) the normally open contacts are in positions 5-7 Alarm and 8-10 Trip, they switch only when the
pre-set temperature limits are reached.
By setting YES (Fail safe), the normally closed contacts are in positions 5-7 Alarm and 8-10 Trip, they switch only when the
pre-set temperature limits are reached or as a result of no voltage on the device.
FAULT
By setting YES (Fail safe), contact 11-12 is positioned as normally open, switches (closed) when a fault condition is
identified; see paragraph on alarms and ventilation on page 17.
Setting NO (NO Fail safe) the contact 11-12 is positioned as normally closed, switches (open) when a fault condition is
identified; see paragraph on alarms and ventilation on page 17.
If the fail safe function is disabled on the fault contact, the control unit will no longer be able to signal the fault due to power
failure. In this case it is advisable to enable the Fail safe on the ALARM contact for the afore-mentioned indication.
NOTE: NOTE: when the control unit is in one of the modes indicated below, it does not perform any thermal monitoring,
moreover the relays will all be disabled the FAULT LED will flash.
• Vis. display programming.
• PRG programming.
• Test of the relays.
The FAIL SAFE function is temporarily disabled and the FAULT relay switches.
ATTENTION: Entering the relay test mode will temporarily disable the fail-safe function, relays with
enabled function switch (ALARM-TRIP-FAULT).
